Hindawi Publishing Corporation Journal of Nanotechnology Volume 2013, Article ID 578684, 9 pages http://dx.doi.org/10.1155/2013/578684 Research Article Synthesis by Microwaves of Bimetallic Nano-Rhodium-Palladium M. Ugalde, 1,2 E. Chavira, 2 M. T. Ochoa-Lara, 1 I. A. Figueroa, 2 C. Quintanar, 3 and A. Tejeda 2 1 Laboratorio Nacional de Nanotecnolog´ ıa, Centro de Investigaci´ on en Materiales Avanzados, S.C., Avenida Miguel de Cervantes 120, 31109 Chihuahua, CHIH, Mexico 2 Instituto de Investigaciones en Materiales, Universidad Nacional Aut´ onoma de M´ exico, Apartado Postal 70-360, 04510 M´ exico, DF, Mexico 3 Facultad de Ciencias, Ciudad Universitaria, Universidad 3000, Circuito Exterior S/N, 04510 M´ exico, DF Mexico Correspondence should be addressed to M. Ugalde; magali.ugalde@cimav.edu.mx Received 29 May 2013; Revised 31 August 2013; Accepted 12 September 2013 Academic Editor: Jorge Seminario Copyright © 2013 M. Ugalde et al. Tis is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. An improved acrylamide sol-gel technique using a microwave oven in order to synthesize bimetallic Rh-Pd particles is reported and discussed. Te synthesis of Pd and Rh nanoparticles was carried out separately. Te polymerization to form the gel of both Rh and Pd was carried out at 80 ∘ C under constant agitations. Te method chosen to prepare the Rh and Pd xerogels involved the decomposition of both gels. Te process begins by steadily increasing the temperature of the gel inside a microwave oven (from 80 ∘ C to 170 ∘ C). In order to eliminate the by-products generated during the sol-gel reaction, a heat treatment at a temperature of 1000 ∘ C for 2 h in inert atmosphere was carried out. Afer the heat treatment, the particle size increased from 50 nm to 200 nm, producing the bimetallic Rh-Pd clusters. It can be concluded that the reported microwave-assisted, sol-gel method was able to obtain nano-bimetallic Rh-Pd particles with an average size of 75 nm. 1. Introduction Bimetallic alloy (solid solutions or intermetallics com- pounds) nanostructures, synthesized from two single com- ponents, have been of interest because of their superior prop- erties, in comparison with their respective single-component species, that is, Ag, Pd, Rh, and so forth [1]. Te synthesis of noble metals and alloys, in nanometric scale, has been extensively investigated in nanotechnology because of their optical and electronic properties, as well as for their useful applications in many felds such as medicine [2], catalysis, and sensors [3–6]. Hardness, high melting and boiling points, and high thermal and electrical conductivity are some of the existing properties of these noble metals. Rhodium and palladium (Rh and Pd) crystallize in a face centered cubic (fcc) unit cell. Both metals add s electrons to the collective d band of palladium [7] and increase the lattice parameter of the palladium host lattice [8, 9]. It was found that rhodium behaves as an absorber of hydrogen at high pressure of gaseous hydrogen when situated within the palladium lattice [10, 11]. Recently, Pd nanocrystals have been prepared in aqueous solutions giving rise to a great variety of shapes, including truncated octahedron, cube, octahedron, and thin plate [12– 14], making them ideal candidates as seeds for growing bimetallic nanostructures. Te control of crystal size and its dispersion are among the main goals of nanocrystal preparation. Tis is due to the physicochemical properties of a bimetallic nanocrystal that can be tailored by controlling their particle size, shape, and elemental composition, as well as their internal and surface structures. Recently, the complexity of nanomaterials can be further enhanced by the formation of multimetallic nanostructures (e.g., core- shell and dumbbell). Synthesis parameters such as capping agent, metal ion, and reaction temperature also play an important role in the overgrowth process [15]. Among the available methods to obtain nanosized bimetallic particles of rhodium-palladium are the coimpregnation method [16, 17],